The victims, aged 51 and 61, were killed in the region of Castilla La Mancha after torrential rain dragged their car and flipped it over.
Two siblings died on Thursday when floodwaters caused by torrential rain dragged their car and flipped it over in eastern Spain, local emergency services said, as authorities warned residents to brace for further storms across large parts of the country.
The victims, aged 51 and 61, were killed in the region of Castilla La Mancha, a spokesman for the government delegation in the region said. In the neighbouring Valencia region, at least two rivers burst their banks, forcing the evacuation of dozens of people.
Authorities had earlier said the victims were an elderly couple, both aged 70.
Severe weather warnings have been issued for Friday for much of southeastern Spain.
Torrential rains swept cars away and blocked roads in Orihuela, in the province of Alicante in southeastern Spain. On Thursday afternoon, military emergency services teams arrived in the town and other affected areas.
The Clariano river flooded parts of Ontinyent, south of the coastal town of Valencia, while television footage showed a deluge tumbling through the streets of nearby Mogente, sweeping debris along with it.
"We had 300 millimetres of rain. We haven't seen that for a century," Jorge Rodríguez, the mayor of Ontinyent, told state broadcaster TVE.
Schools in Valencia and the Murcia region suspended classes, expecting the heavy rains to continue. Local authorities recommended people stay in their homes in the worst-affected areas, where the weather interrupted traffic on roads and railways and at ports.